Download system initial incubation temperature modification study

Abstract 60
DNA IQ™ SYSTEM INITIAL INCUBATION TEMPERATURE MODIFICATION STUDY
Gretchen DeGroot, M.S., Susie J. Odogba, M.S., M.S.Ed
Wisconsin State Crime Lab-Milwaukee, 1578 S. 11th St, Milwaukee, Wisconsin 53204,
USA
A comparative analysis of the initial incubation temperature (at 95º C) for the DNA IQ™
System was performed in the Wisconsin State Crime Laboratory-Milwaukee. The
purpose of conducting this study was due to a temperature modification (from 95º C to
70º C) by the manufacturer, Promega Corporation. The type of samples utilized for this
study consisted of diluted blood and semen stains. The whole blood was diluted one
eighth (1/8), and the neat semen was diluted one sixteenth (1/16); one micro liter of the
aforementioned blood and semen dilutions were spotted onto Whatman’s paper. A sideby-side temperature analysis was conducted on each of the samples. All of the samples
were quantified using the 7000 sequencer; some of the samples (for the 95º C and 70º C
temperature) were amplified and typed employing the Promega’s PowerPlex® 16
System. Approximately one nanogram (ng) of DNA from each of the DNA IQ extracted
samples was amplified. The results obtained from the quantifiler showed that there were
no significant differences between the temperatures for DNA recovery for the diluted
blood samples. However, for the semen-diluted samples the 95º C temperature showed
a consistently higher DNA recovery than the 70º C temperature. Based on the typing
results obtained and the t-test analysis, there were no significant differences in the peak
height ratios due to the 95º C temperature, or the 70º C temperature. A complete DNA
profile was developed from all samples that were consistent with the DNA profile of the
individual from which the samples were collected. In summary, both temperatures
proved suitable for DNA recovery and did not show signs of having a deleterious effect
on the DNA, such that the sample(s) tested failed to yield a suitable DNA profile due to
degradation. However, recovery of as much DNA possible from semen samples for
forensic applications is essential for employing automation within our laboratory system.